In the period between 1945 and 198S, 30 species of insects, excluding mosquitoes and beneficials, are known to have been accidentally introduced to Guam. Of these, 11 were introduced between 1945 and 1955 (1.1 per year), 7 more between 1955 and 1970(0.5 per year), and 17 since 1970(1.1 per year). The number of introductions roughly corresponds to the amount of traffic to and from Guam during the period in question. Prior to 1975, most of the new introductions probably arrived from Asia or other islands in Micronesia, but since 197S, Hawaii appears to be the source of at least half of the new introductions.